The present invention relates to a semiconductor integrated circuit device and, more particularly, to a technology which is effective for use in a semiconductor integrated circuit device including a RAM (i.e., Random Access Memory) having dynamic memory cells to be backed up by a relatively low voltage of a battery.
There has been proposed in Japanese Patent Laid-Open No. 83293/1985 a dynamic RAM which is composed of a plurality of dummy cells so that the amount of stored data may be monitored with the data storage level of the dummy cells to start an automatic refresh circuit before the data are lost.